Antifungal Shoe Insole with Built-In Ultraviolet LED

ABSTRACT

A shoe insole with one or more ultraviolet LEDs that is used to prevent or eliminate foot fungus. In the preferred embodiment the built-in LED and battery combination will have a designed lifetime that coincides with the designated shelf life of the insole. In the preferred embodiment the insole would be a replaceable insole and would be disposed of after its designated lifetime or sent in for recycling.

BACKGROUND OF THE INVENTION

The antifungal shoe insole with built-in ultraviolet LED is intended to be a mass consumer product. The engineering of this insole combines the fields of science of photobiology and optoelectronics with electrical circuit design.

Ultraviolet germicidal irradiation (UVGI) is known to be an effective method of killing a broad range of microbes. Wavelengths at or near 2537 Angstroms are uniquely destructive to microbes due to the fact that it corresponds to the structural resonance of DNA for microorganisms. In this insole the source of the UVGI is an ultraviolet LED.

UVGI inactivates pathogens according to the standard decay equation S=EXP(−klt) where S represents the fraction of the original pathogen population that survives exposure time t, and l represents the UVGI intensity. The rate constant k has been determined experimentally for a number of bacteria, viruses, and spores at different power levels.

In the case of this insole the time t and the desired S would be determined by the efficacy requirement for marketing the product.

The optical radiation emitted by the LED is strongly correlated to the electrical current. And the electrical current correlates to the lifetime of the battery which powers it according to the equation life(hours)=(ampere-hour rating)/(amperes drawn).

Design criteria for the circuit involve determination of current requirements to reach desired UVGI intensity that meet efficacy requirements. Commercial availability and cost of the battery and LED are also considerations in the final selection of the components.

Continuous advancement in LED and battery technology are working to increase the efficacy and decrease the cost of this product ensuring its commercial viability.

REFERENCES

-   1. Penn State Department of Architectural Engineering (2006).     “Ultraviolet Irradiation”. Web. -   2. Labsphere.com (2006). “The Radiometry of Light Emitting Diodes”.     Web.

DRAWINGS Figures

FIG. 1 shows top view of shoe insole with one LED

FIG. 2 shows side view of shoe insole

FIG. 3 shows top view of shoe insole with multiple LEDs

FIG. 4 shows electrical schematic

REFERENCE NUMERALS

-   10 Ultraviolet LED -   11 Battery -   12 Timer -   13 Contact Pressure Switch -   14 Light Activated Switch -   15 Mirrored Surface -   16 Semi-Transparent Surface -   17 Solar Cell

DETAILED DESCRIPTION FIGS. 1, 2, 3, and 4

FIG. 1 shows the top view of the insole with one LED. All electronic components are shown sealed within the insole. The ultraviolet LED 10 is shown in the rear heel of the insole. It illuminates the entire surface area of the insole. The battery 11 is shown in the heel of the insole. In the preferred embodiment it is sealed within the insole. The timer 12 and contact pressure switch 13 are shown in the heel of the insole. The light activated switch 14 is shown in the toe of the insole.

FIG. 2 shows the side view of the insole. The ultraviolet LED 10 and battery 11 are at the heel of the insole. The ultraviolet LED illuminates the entire area of the insole through the cavity shown within the insole. The light emitted by the LED is reflected by the mirrored surface 15 shown at the bottom of the insole and reflected unto the semi transparent surface 16 which is shown as the top surface upon which the foot rests.

FIG. 3 shows the top view of the insole with multiple LEDs. All electronic components are shown sealed within the insole. As in FIG. 1 the battery 11 timer 12 and contact pressure switch 13 are shown in the heel of the insole. The ultraviolet LEDs 10 are spaced evenly within the insole and illuminate the entire surface area of the insole. A solar cell 17 is shown in the toe of the insole. The solar cell is shown built into the insole.

FIG. 4 shows a sample electrical schematic of the circuit in the insole. In the preferred embodiment all components shown are sealed within the insole. As shown the ultraviolet LED 10 is powered by the battery 11 and the circuit is energized by the activation of the contact pressure switch 13.

The one or more LEDs in the insole are positioned for uniform dispersion of the light via the mirrored surface onto the semi transparent anti fungal surface.

All electronic components are positioned for efficient use of space as well as to minimize foot pressure on the components.

Operation

This insole described has the structure of an ordinary replaceable insole with the addition of electronics and materials within the insole which facilitate the elimination of foot fungus by ultraviolet germicidal irradiation (UVGI) automatically.

The source of the UVGI in this insole are one or more ultraviolet LEDs 10 which emit at or near the resonant frequency of DNA for microorganisms. The foot fungus spores are killed by UVGI in a process similar to other microorganisms as predicted by the standard decay equation. See specification—background of the invention.

In the preferred embodiment the user would simply purchase the insole and place it in their shoe. The UVGI anti fungal action would be initiated automatically by the contact pressure switch 13 and controlled by the timer. The light activated switch 14 can be used as an additional interlock so that the device cannot be activated outside the shoe.

The contact pressure switch 13 can be configured so that the UVGI anti fungal action is activated when the foot is present in order to sanitize the foot. Or it can be configured so that the anti fungal action is activated when the foot is not present in order to sanitize the inside of the shoe.

In the preferred embodiment the battery 11 is sealed within the insole so the device would have a limited lifetime. This lifetime can be calibrated based on the required time to kill the foot fungus as calculated using the standard decay equation as well as the number of such cycles needed for marketing of the product.

An additional embodiment utilizing a built in solar cell 17 can be used as a more permanent long lasting solution. The solar cell 17 can be used as a standalone power source or as an adjunct to the battery 11. In this embodiment the user would place the insole in the light to initiate the anti fungal action and sanitize the insole or to recharge the battery 11.

In the preferred embodiment the insoles would come prepackaged as matched pair with simple instructions on how to place the device within the shoe as well as an indication of how long the anti fungal action is good for. The user would use the device for the indicated length of time and then dispose of the insoles. 

1. A shoe insole with one or more built-in ultraviolet LEDs and a DC power source.
 2. The insole in claim 1 is a replaceable insole.
 3. The insole in claim 1 is permanently attached to the shoe.
 4. The DC power source in claim 1 is a battery permanently embedded in the insole.
 5. The DC power source in claim 1 is a replaceable battery.
 6. The DC power source in claim 1 is a solar cell.
 7. The top surface of the insole in claim 1 is made of a semi-transparent material.
 8. The semi-transparent material in claim 7 is a polymer.
 9. The semi-transparent material in claim 7 is a mesh.
 10. The LED or LEDs in claim 1 are on continuously.
 11. The LED or LEDs in claim 1 are controlled by a timer.
 12. The LED or LEDs in claim 1 are pulsed.
 13. The light emitted by the LED or LEDs in claim 1 is propagated through a mirror or a plurality of mirrors.
 14. The light emitted by the LED or LEDs in claim 1 is filtered.
 15. The LED or LEDs in claim 1 are activated by a contact pressure switch.
 16. The LED or LEDs in claim 1 are activated by a light activated switch.
 17. The insole in claim 1 is disposable.
 18. The insole in claim 1 is recyclable. 